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Number of (n+1) X (n+1) 0..2 arrays with every element both >= and <= some horizontal or antidiagonal neighbor.
1

%I #7 Mar 24 2023 10:16:41

%S 9,421,175431,544777651,12109668893083,1861384207351560027,

%T 2008977605538697290717011,15204797339736917181390137180801,

%U 806565211683665167431270425538954014249

%N Number of (n+1) X (n+1) 0..2 arrays with every element both >= and <= some horizontal or antidiagonal neighbor.

%C Diagonal of A232257.

%H R. H. Hardin, <a href="/A232249/b232249.txt">Table of n, a(n) for n = 1..11</a>

%e Some solutions for n=3

%e ..1..1..0..2....1..1..2..1....0..0..2..0....1..1..1..2....0..0..1..1

%e ..1..0..2..1....1..2..0..0....0..2..0..2....2..2..2..1....0..0..0..1

%e ..1..1..0..1....2..2..1..2....2..2..2..1....2..2..0..0....1..2..2..0

%e ..0..0..2..2....2..2..2..2....2..2..0..0....1..0..2..2....1..1..0..0

%Y Cf. A232257.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 21 2013